Display device, projector, display system, and method of switching device

ABSTRACT

A display device is capable of switching a function of an indication body in accordance with the need of the user in the case in which the indication body is made to function as a pointing device. The display device is provided with a function device having a first interface. The configuration information of the first interface is stored in the storage section, and is supplied to a host device by a supply section via the function device. A change section is capable of change the configuration information in accordance with the operation of the user received by a reception section.

BACKGROUND

1. Technical Field

The present invention relates to a technology for recognizing anoperation to a display surface.

2. Related Art

In the past, there has been known a device, which, when a specificposition of an image displayed by a display device such as a projectoris indicated with an indication body, detects the indication position,and then displays a pointer or the like so as to correspond to theposition thus detected (see, e.g., Japanese Patent No. 4272904 (Document1)). By drawing the trajectory of the position detected using the devicedescribed in Document 1, it is possible to display characters, figures,and so on written by hand.

Incidentally, in the case in which the user draws a hand-written imageto the display surface, the information representing the indicationposition of an indication body used for handwriting is sometimes treatedas the information representing the indication position or the like of apointing device (e.g., a mouse and a digitizer). On this occasion, therecan be the case in which the switching from the state of treating theinformation representing the indication position and so on of theindication body as the information representing the indication positionand so on of a certain pointing device to the state of treating theinformation as the information representing the indication position andso on of another pointing device is desired. Further, in the case ofusing a personal computer (PC) as the host device, if the operatingsystem (OS) of the PC or the version thereof is different, there is apossibility that available pointing devices are also different.

SUMMARY

An advantage of some aspects of the invention is to make it possible toswitch the function of the indication body in accordance with the needof the user in the case in which the indication body is made to functionas a pointing device.

A display device according to an aspect of the invention is configuredto include a function device connected to a host device in a mannercompliant with a USB (Universal Serial Bus) standard, and having a firstinterface, a storage section adapted to store a plurality of pieces ofconfiguration information including first configuration informationadapted to make a first pointing device correspond to an interface, adisplay section adapted to display an image on a display surface, adetector adapted to detect a first position indicated by a firstindication body to the display surface, a supply section adapted toassign the first configuration information stored in the storage sectionand first coordinate data representing the first position detected bythe detector to the first interface, and supply the host device with thefirst configuration information and the first coordinate data via thefunction device, a reception section adapted to receive an operation ofa user, and a change section adapted to change the configurationinformation corresponding to the first coordinate data in accordancewith the operation received by the reception section.

According to the display device of this aspect of the invention, it ispossible to change the configuration information assigned to the firstcoordinate data in accordance with the operation of the user.

In a preferable aspect of the invention, the function device includesthe first interface and a second interface, the storage section storesthe first configuration information, and second configurationinformation adapted to assign a second pointing device different fromthe first pointing device to an interface, the change section changesthe interface, to which the supply section supplies the first coordinatedata, from the first interface to the second interface in accordancewith the operation, and the supply section assigns the secondconfiguration information and the first coordinate data to the secondinterface, and supply the host device with the second configurationinformation and the first coordinate data via the function device.

According to this preferable aspect of the invention, it is possible tochange the configuration information assigned to the first coordinatedata by switching the interface, and there is no need to change theconfiguration information itself.

In another preferable aspect of the invention, the function deviceincludes the first interface and a second interface, the storage sectionstores the first configuration information, and second configurationinformation adapted to assign a second pointing device different fromthe first pointing device to an interface, the detector detects thefirst position, and a second position indicated by a second indicationbody to the display surface, the supply section assigns the firstconfiguration information stored in the storage section and the firstcoordinate data representing the first position detected by the detectorto the first interface and supplies the host device with the firstconfiguration information and the first coordinate data via the functiondevice, and assigns the second configuration information stored in thestorage section and second coordinate data representing the secondposition detected by the detector to the second interface and suppliesthe host device with the second configuration information and the secondcoordinate data via the function device, and the change section changesat least either of the first configuration information and the secondconfiguration information supplied from the supply section in accordancewith the operation received by the reception section.

According to this preferable aspect of the invention, it is possible tochange each of the first configuration information and the secondconfiguration information in accordance with the operation of the user.

In still another preferable aspect of the invention, the change sectionchanges the configuration information so that a class of a deviceassigned to the first interface from one of a mouse and a digitizer tothe other.

According to this preferable aspect of the invention, it is possible touse the indication body as a mouse or a digitizer.

In yet another preferable aspect of the invention, the storage sectionstores the configuration information, which assigns HID (Human InterfaceDevice) class to the first interface and the second interface.

According to this preferable aspect of the invention, it is possible torecognize a plurality of indication bodies without installing thededicated device driver in the host device.

In this case, the storage section may store the configurationinformation, which assigns a sub-class corresponding to a mouse to thefirst interface, and assigns a sub-class corresponding to a digitizer tothe second interface.

According to this preferable aspect of the invention, a plurality ofindication bodies can be recognized as the pointing devices differentfrom each other.

Alternatively, the storage section may store the configurationinformation, which assigns a sub-class corresponding to a mouse to thefirst interface and the second interface, or may store the configurationinformation, which assigns a sub-class corresponding to a digitizer tothe first interface and the second interface.

A projector according to another aspect of the invention is configuredto include a function device connected to a host device in a mannercompliant with a USB standard, and having a first interface, a storagesection adapted to store a plurality of pieces of configurationinformation including first configuration information adapted to make afirst pointing device correspond to an interface, a display sectionadapted to display an image on a display surface by projecting light, adetector adapted to detect a first position indicated by a firstindication body to the display surface, a supply section adapted toassign the first configuration information stored in the storage sectionand first coordinate data representing the first position detected bythe detector to the first interface, and supply the host device with thefirst configuration information and the first coordinate data via thefunction device, a reception section adapted to receive an operation ofa user, and a change section adapted to change the configurationinformation corresponding to the first coordinate data in accordancewith the operation received by the reception section.

According to the projector of this aspect of the invention, it ispossible to change the configuration information assigned to the firstcoordinate data in accordance with the operation of the user.

A display system according to still another aspect of the invention isconfigured to include the display device and the first indication bodydescribed above, and a host device including an execution sectionadapted to execute a process corresponding to the first position inaccordance with the configuration information and the first coordinatedata supplied via the function device.

According to the display system of this aspect of the invention, it ispossible to change the configuration information assigned to the firstcoordinate data in accordance with the operation of the user.

In a preferable aspect of the invention, the execution section executesa process of making the display section draw an image corresponding tothe first position.

According to this preferable aspect of the invention, it is possible toreflect the indication by the indication body on the display by thedisplay device.

A method of switching a device according to yet another aspect of theinvention is a method of switching a device in a display device. Thedisplay device includes a function device connected to a host device ina manner compliant with a USB standard, and having a first interface, astorage section adapted to store a plurality of pieces of configurationinformation including first configuration information adapted to make afirst pointing device correspond to an interface, and a display sectionadapted to display an image on a display surface. The method includes afirst step of detecting a position indicated by an indication body tothe display surface, a second step of assigning coordinate datarepresenting the position detected in the first step and theconfiguration information stored in the storage section to the firstinterface, and supplying the host device with the coordinate data andthe configuration information via the function device, a third step ofreceiving an operation of changing the configuration information, whichis assigned to the first interface, from a user, a fourth step ofchanging the configuration information corresponding to the coordinatedata from the coordinate data supplied in second step in accordance withthe operation received in the third step, a fifth step of detecting,after the change in fourth step, a position indicated by the indicationbody to the display surface, and a sixth step of assigning coordinatedata representing the position detected in the fifth step and theconfiguration information changed in fourth step to the first interface,and supplying the host device with the coordinate data and theconfiguration information via the function device.

According to the switching method of this aspect of the invention, it ispossible to change the configuration information assigned to thecoordinate data in accordance with the operation of the user.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a block diagram showing a functional configuration of adisplay system.

FIG. 2 is a diagram showing a configuration of the display system.

FIG. 3 is a block diagram showing a configuration of a projector.

FIG. 4 is a block diagram showing a configuration of a PC.

FIG. 5 is a diagram showing an example of an appearance of a pen.

FIG. 6 is a block diagram showing a configuration of the pen.

FIGS. 7A and 7B are diagrams exemplifying images displayed by theprojector.

FIGS. 8A and 8B are explanatory diagrams showing the procedure of theprocess of detecting and converting the coordinate.

FIG. 9 is a flowchart showing an operation of the projector.

FIG. 10 is a flowchart showing an operation of the projector.

FIG. 11 is a diagram for exemplifying an OSD image.

FIG. 12 is a diagram for exemplifying an OSD image.

FIG. 13 is a diagram for exemplifying an OSD image.

DESCRIPTION OF AN EXEMPLARY EMBODIMENT

Overview of Invention

One feature of the invention resides in making it possible for the userto switch the function of an indication body in a display system capableof performing the process corresponding to the indication on the displaysurface made by the user using the indication body. Here, the functionof the indication body denotes the function recognized in the hostdevice. With the display system according to the invention, it ispossible for the user to make the indication body function as a mouse orfunction as a digitizer according to the need while using the sameindication body. It is assumed that the display system according to theinvention performs the connection between a host device and a displaydevice in a manner compliant with the USB standard in the configurationprovided with the display device for displaying one or a plurality ofindication bodies and an image, and detecting the position indicated bythe indication body, and the host device for performing the processcorresponding to the indication by the indication body.

It should be noted that in the invention use of a plurality ofindication bodies by a single user is not excluded. However, for thesake of convenience of explanation, it is assumed hereinafter that asingle user uses one indication body, and further, the number of usersperforming indication to the display surface is two. In other words, adisplay system in which two users use one indication body for each,totally two indication bodies will hereinafter be explained.

FIG. 1 is a block diagram showing a functional configuration of adisplay system 1 according to an embodiment of the invention. Thedisplay system 1 is provided at least with a display device 10,indication bodies 20 a, 20 b, and a host device 30. The display device10 can be a device provided with the constituents shown in FIG. 1integrally (i.e., in a single device), or a device realizing theconstituents by cooperative operations of a plurality of devices.

The display device 10 is provided with a function device 11, a storagesection 12, a display section 13, a detector 14, a supply section 15, areception section 16, and a change section 17. Further, the host device30 is provided with a host controller 31, and an execution section 32.The host controller 31 and the function device 11 are connected to eachother via, for example, a USB cable, but can also be connected in awireless manner via wireless USB or the like.

The function device 11 is a device for connecting the display device 10to the host device 30. The function device 11 is configured so as to becompliant with the USB standard, and has a first interface 11 a and asecond interface 11 b. The first interface 11 a and the second interface11 b are each configured including one or more endpoints. In otherwords, the function device 11 is a so-called composite device.

The storage section 12 is a device for storing configurationinformation. Here, the configuration information is the data(descriptor) for defining the configuration of the function device 11,and represents what class of device the host device 30 recognizes thefunction device 11 as. The configuration information is the informationfor providing the interfaces with correspondence with predeterminedpointing devices. The class assigned to the first interface 11 a and thesecond interface 11 b is preferably the human interface device (HID)class, which is a general-purpose class, but can be a unique classdefined by a vendor or the like. The configuration information of theembodiment of the invention includes the information representing thesubclass (e.g., a mouse and a digitizer) besides the informationrepresenting the class. In the case of the HID class, the configurationinformation is described by a report descriptor. For example, in theconfiguration information of the mouse, the Usage Page is “GenericDesktop Page (0X01),” and in the configuration information of thedigitizer, the Usage Page is “Digitizers (0X0D).”

The display section 13 is a device for displaying the image on thedisplay surface. The display section 13 can be a device such as a liquidcrystal display or an organic electroluminescence (EL) display providedwith the display surface itself, or can be a device such as a projectorusing a screen, a wall surface, and so on as the display surface, anddisplaying an image by projecting light on the display surface.

The detector 14 is a device for detecting the position at which the userhas performed indication to the display surface with the indicationbodies 20 a, 20 b. The detector 14 optically detects or magneticallydetects the indication by the indication bodies 20 a, 20 b, but thedetection method itself is not particularly limited. The detector 14outputs coordinate data representing the position thus detected. Itshould be noted that the indication bodies 20 a, 20 b are tools for theuser to point the display surface, and are each, for example, a rod liketool imitating a writing material. However, the indication bodies 20 a,20 b can each take any specific shape providing the indication bodiescan point the display surface. One of the indication bodies 20 a, 20 bcorresponds to a first indication body according to the invention, andthe other thereof corresponds to a second indication body according tothe invention.

It is also possible for the detector 14 to further have a function ofdiscriminating the indication bodies 20 a, 20 b indicating the positionsin addition to the function of detecting the positions indicated by theindication bodies 20 a, 20 b. For example, in the case of theconfiguration in which the indication bodies 20 a, 20 b emit light andthen the detector 14 detects the light, it is possible to discriminatethe indication bodies 20 a, 20 b from each other based on the colors(i.e., the wavelengths) of the light emitted by the indication bodies 20a, 20 b or the illumination patterns (the timing of blinking) thereof.

The detector 14 can detect the plurality of positions indicated by theindication bodies 20 a, 20 b, respectively, and then output them asseparate coordinate data. Here, the coordinate data representing thepositions indicated by the indication bodies 20 a, 20 b are referred toas “first coordinate data” and “second coordinate data,” respectively.If the detector 14 can discriminate the indication bodies 20 a, 20 bfrom each other, it is possible to make the first coordinate data andthe second coordinate data have correspondence with the specificindication bodies in such a manner that, for example, the firstcoordinate data corresponds to the position indicated by the indicationbody 20 a, and the second coordinate data corresponds to the positionindicated by the indication body 20 b.

The supply section 15 is a device for supplying the host device 30 withdata via the function device 11. The supply section 15 supplies theconfiguration information in the process of enumeration, and thensupplies the coordinate data. Specifically, the supply section 15assigns the first coordinate data to the first interface 11 a, and atthe same time, assigns the second coordinate data to the secondinterface 11 b, and then supplies the respective data.

The reception section 16 is a device for receiving the operation of theuser. It is also possible for the reception section 16 to have aconfiguration of receiving the operation of the user via a buttonprovided to the display device 10, or to have a configuration providedwith a receiver section for receiving a wireless signal (e.g., aninfrared signal) and for receiving the operation of the user via aremote controller for emitting the wireless signal. Further, it is alsopossible for the reception section 16 to have a configuration ofreceiving the indication by the indication bodies 20 a, 20 b to a partof the on-screen display (OSD) image described later as the operation ofthe user.

The change section 17 is a device for changing the configurationinformation supplied by the supply section 15. When the receptionsection 16 receives the operation of the user, the change section 17changes the configuration information in accordance with the operation.The configuration information supplied by the supply section 15 to thehost device 30 is determined in advance. Although the change section 17changes at least one of the configuration information respectivelyassigned to the first interface 11 a and the second interface 11 b, itis also possible for the change section 17 to change the both at thesame time.

The host controller 31 is a device for connecting the host device 30 tothe display device 10. The host controller 31 is configured in a mannercompliant with the USB standard.

The execution section 32 is a device for performing the processcorresponding to the position detected by the detector 14. The executionsection 32 is capable of identifying the first coordinate data assignedto the first interface 11 a and the second coordinate data assigned tothe second interface 11 b, and then performing the processescorresponding to the respective coordinate data. The process performedby the execution section 32 is different in accordance with the positiondetected by the detector 14 and the image displayed at the position bythe display device 10, but is, for example, for changing the imagedisplayed on the display surface, or for controlling the operation ofthe display device 10 in accordance with the indication to the menu bardescribed later. The processes performed by the execution section 32include a process of drawing a pointer or a hand-written image, and aprocess for receiving a change in the configuration information.

Configuration of Embodiment

FIG. 2 is a diagram showing a configuration of an example of the displaysystem 1 described above as a specific embodiment of the invention.

The projector 100 is connected to a personal computer (PC) 300 as theinformation processing device via an image signal cable or the like in awired manner. The image data is input from the PC 300 to the projector100, and the projector 100 projects an image on the screen SC as aprojection surface (the display surface) based on the image data thusinput. Further, the projector 100 is connected to the PC 300 with theUSB cable or the like, and transmits/receives the control data and so onto/from the PC 300. The projector 100 can perform projectionirrespective of whether the image data input from the PC 300 is a stillimage or a moving image. It is also possible for the projector 100 touse the wall surface itself as the screen SC besides a flat plate fixedto the wall surface. Here, the range in which the image is projected onthe screen SC is defined as an actual projection area A12 (a displayablearea).

Here, the projector 100 corresponds to an example of the display device10 shown in FIG. 1. Further, the PC 300 corresponds to an example of thehost device 30 shown in FIG. 1, and a pen 200 corresponds to an exampleof the indication bodies 20 a, 20 b shown in FIG. 1. It should be notedthat although the pen 200 alone is shown in FIG. 2, it is assumed thattwo or more pens 200 actually exist correspond respectively to two ormore users. It is assumed in the present embodiment that the number ofusers is two at most.

In the display system 1, the user can perform the operation (positionindication operation) of indicating an arbitrary position in the actualprojection area A12 of the screen SC with the pen 200 in the hand by ahandwriting operation during the projection of the image by theprojector 100. The pen 200 is an operation device having a pen-likeshape or a rod shape, and is used for indicating an arbitrary positionon the screen SC. The projector 100 has a function of detecting theposition indicated by the pen 200 as described later, and outputscoordinate data (coordinate information) representing the coordinate ofthe position thus detected to the PC 300.

It should be noted here that “handwriting” means that characters andfigures can be drawn as if the user actually writes them with a writingmaterial in accordance with the indication with the indication body, butdoes not mean that the user actually draws the characters and figures onthe display surface while coloring them with color materials such asink. It should be noted that hereinafter the characters and figuresdrawn by the user on the display surface are also referred collectivelyto “symbols.” The symbols mentioned here can include numbers, signs,scientific symbols, and so on besides characters of a variety oflanguages. Further, figures include dots and lines besides circles andpolygons.

FIG. 3 is a block diagram showing a configuration of the projector 100.

According to a rough classification, the projector 100 is provided witha position detection unit 110 for detecting the indication position ofthe pen 200 on the screen SC, a coordinate conversion section 120 forconverting the coordinate of the indication position detected by theposition detection unit 110 into the coordinate in the image data, animage processing unit 130 for performing image processing for displaybased on the image data input from the PC 300, a projection unit 140 forprojecting the image on the screen SC in accordance with the control ofthe image processing unit 130, an output section 150 for outputting thecoordinate thus converted into by the coordinate conversion section 120,an input section 160, a control section 170 for controlling each ofthese constituents, a storage section 180, and an operation section 190for receiving operations by the user.

The control section 170 is composed of a central processing unit (CPU),a nonvolatile memory, a random access memory (RAM), and so on not shown,and reads out and then executes a control program stored in the storagesection 180 connected to the control section 170 to thereby control eachsection of the projector 100. Further, by executing the control programstored in the storage section 180, the control section 170 performs acalibration described later. The control section 170 performs thecalibration described to thereby obtain parameters (coordinateconversion parameters) representing the correspondence relationshipbetween the coordinate in shot image data and the coordinate in the area(e.g., the actual projection area A12) on the screen SC to be the objectof the calibration. The storage section 180 is formed of a magnetic oroptical recording device, or a semiconductor storage element, and storesa variety of types of programs including the control program, and datasuch as various setting values.

The operation section 190 is connected to the control section 170. Theoperation section 190 is provided with a variety of switches andindicator lamps, and can also be provided with an operation paneldisposed on an exterior housing (not shown) of the projector 100, or canalso be provided with a receiving section for receiving an infraredsignal from a so-called remote controller. The control section 170appropriately lights or blinks the indicator lamps in accordance withthe operation state and the setting state of the projector 100. Further,when the switch of the operation section 190 is operated, the operationsignal corresponding to the switch thus operated is output to thecontrol section 170. It should be noted that the operation section 190is not limited to the infrared signal, but can also have a configurationof receiving other wireless signals. The operation section 190corresponds to the reception section 16 shown in FIG. 1.

Further, in the case in which the display system 1 includes the remotecontroller, the projector 100 receives the infrared signal, which theremote controller (not shown) used by the user of the projector 100transmits in accordance with the button operation. The operation section190 receives the infrared signal received from the remote controllerwith a light receiving element, and then outputs an operation signalcorresponding to this signal to the control section 170. It should benoted that it is also possible to transmit an operation signalrepresenting the operation with respect to the projector 100 from the PC300 to the projector 100 to thereby control the projector 100 based onthe operation signal. In this case, the PC 300 also functions as theoperation section for the user to input the operation with respect tothe projector 100.

The control section 170 detects the operation of the user based on theoperation signal input from the operation section 190, and then controlsthe projector 100 in accordance with this operation. For example, basedon the operation signal input from the operation section 190, thecontrol section 170 changes the configuration information assigned tothe first interface 11 a and the second interface 11 b. In other words,the control section 170 corresponds to the change section 17 shown inFIG. 1.

The input section 160 is an interface for connecting the projector 100to the PC 300. The input section 160 is an interface for inputting imagedata, and there can be used therefor a general-purpose interface such asan interface to which a digital video signal is input such as a DVI(Digital Visual Interface), a USB (Universal Serial Bus) interface, or aLAN (Local Area Network) interface, the S-video terminal to which thevideo signal such as NTSC (National Television System Committee), PAL(Phase Alternating Line), and SECAM (Sequentiel couleur a memoire), anRCA terminal to which a composite video signal is input, a D-terminal towhich a component video signal is input, or an HDMI (High-DefinitionMultimedia Interface, a registered trademark) connector compliant withthe HDMI standard. Further, it is also possible to adopt a configurationin which the input section 160 has an A/D conversion circuit forconverting an analog video signal into digital image data, and isconnected to the PC 300 with an analog video terminal such as a VGA(Video Graphics Array) terminal. It should be noted that it is alsopossible for the input section 160 to perform transmission/reception ofthe image signal using wired communication, or to performtransmission/reception of the image signal using wireless communication.

Further, the input section 160 can also have a configuration providedwith a DisplayPort developed by the Video Electronics StandardAssociation (VESA), and specifically, it can also have a configurationprovided with a DisplayPort connector or a Mini-DisplayPort connector,and an interface circuit compliant with the DisplayPort standard. Inthis case, the projector 100 can be connected to the DisplayPortprovided to the PC 300 or a portable device having an equivalentfunction to the PC 300.

The configuration of the projector 100 is classified into an opticalsystem for performing optical image formation and an image processingsystem for electrically processing the image signal. The optical systemis composed of an illumination optical system 144, a light modulationdevice 145, and a projection optical system 146. The illuminationoptical system 144 is provided with a light source formed of a xenonlamp, a super-high pressure mercury lamp, a light emitting diode (LED),a laser, or the like. Further, the illumination optical system 144 canalso be provided with a reflector and an auxiliary reflector for guidingthe light emitted by the light source to the light modulation device145, and can be a system provided with, for example, a lens group forimproving the optical characteristics of the projection light, apolarization plate, or a photochromic element for reducing the lightintensity of the light emitted by the light source on the path leadingto the light modulation device 145.

The light modulation device 145 receives the signal from the imageprocessing system described later, and then modulates the light from theillumination optical system 144. In the present embodiment, theexplanation will be presented citing the case of configuring the lightmodulation device 145 using a transmissive liquid crystal panel as anexample. In this configuration, the light modulation device 145 iscomposed of three liquid crystal panels corresponding respectively tothe three primary colors of red (R), green (G), and blue (B) in order toperform color projection. The liquid crystal panels each have apredetermined number of pixels arranged, for example, vertically andhorizontally in a matrix. The light from the illumination optical system144 is separated into colored lights of three colors of RGB, and thecolored lights enter the corresponding liquid crystal panels,respectively. The colored lights modulated while passing through therespective liquid crystal panels are combined by a combining opticalsystem such as a cross dichroic prism, and are then output to theprojection optical system 146.

The projection optical system 146 is provided with, for example, a zoomlens for performing expansion and contraction of the image to beprojected and adjustment of the focus, a zoom controlling motor forcontrolling the level of the zoom, and a focus adjusting motor forperforming the focus adjustment.

The projection unit 140 is provided with a projection optical systemdrive section 143 for driving the motors provided to the projectionoptical system 146 in accordance with the control by the display controlsection 132, a light modulation device drive section 142 for driving thelight modulation device 145 based on the image signal output from thedisplay control section 132, and a light source drive section 141 fordriving the light source provided to the illumination optical system 144in accordance with the control by the control section 170. Theprojection unit 140 corresponds to the display section 13 shown in FIG.1.

On the other hand, the image processing system is formed of the imageprocessing unit 130 for processing the image data in accordance with thecontrol by the control section 170 for integrally controlling the wholeof the projector 100. The image processing unit 130 is provided with animage input section 131 for inputting the image data from the inputsection 160, the display control section 132 for processing the imagedata input via the image input section 131, and an image processingsection 133 for developing the image on a frame memory 134 in accordancewith the control of the display control section 132 to thereby generatethe image to be projected by the projection section 30.

The display control section 132 performs discrimination of the format(the frame rate, the resolution, and the compression state) of the imagedata input via the image input section 131, and so on to therebydetermine the necessary process for displaying the display image on thelight modulation device 145, and then controls the image processingsection 133 to perform the process. The image processing section 133develops the image data, which is input via the image input section 131,on the frame memory 134 in accordance with the control of the displaycontrol section 132, then performs various conversion processes such asinterlace/progressive conversion, or resolution conversion if necessaryto thereby generate the image signal with a predetermined format fordisplaying the display image drawn on the frame memory 134, and thenoutputs it to the display control section 132. It should be noted thatthe projector 100 can also perform the display after changing theresolution and the aspect ratio of the image data thus input, or performthe display while keeping the resolution and the aspect ratio of theimage data thus input in a dot-by-dot manner. Further, the imageprocessing section 133 can perform various types of image processingsuch as a keystone correction, a color compensation corresponding to acolor mode, and image expansion/contraction process in accordance withthe control of the display control section 132. The display controlsection 132 outputs the image signal processed by the image processingsection 133 to the light modulation device drive section 142 to displayit on the light modulation device 145. Further, the image processingsection 133 obtains the image position information based on theinformation such as the resolution and the aspect ratio of the imagedata presently displayed, and the display size in the liquid crystalpanel of the light modulation device 145, and then outputs the imageposition information thus obtained to the coordinate conversion section120. The image position information is the information representing whatposition in the actual projection area A12 the display image isprojected (displayed) at. In other words, the image position informationis the information related to the location of the display image in theactual projection area A12, and represents the position (location) ofthe display image in the actual projection area A12. The image positioninformation varies in the case (e.g., the case in which the setting withrespect to the resolution is changed in the PC 300) in which, forexample, the resolution of the image data output by the PC 300 to theprojector 100 is varied due to the variation in the display resolutionof the PC 300.

The control section 170 performs the control program to thereby controlthe display control section 132 to execute the keystone correction ofthe display image imaged on the screen SC. Further, the control section170 controls the display control section 132 to execute theexpansion/contraction processes of the display image based on theoperation signal input from the operation section 190.

The projector 100 has the position detection unit 110 for detecting theindication position indicated by the pen 200 on the screen SC. Theposition detection unit 110 is provided with an imaging section 111 forshooting the screen SC, a shooting control section 112 for controllingthe imaging section 111, and a position detection processing section 113for detecting the indication position of the pen 200 based on the shotimage of the imaging section 111, and a coordinate calculation section114 for calculating the coordinate of the indication position. Theposition detection unit 110 corresponds to the detector 14 shown in FIG.1.

The imaging section 111 is a digital camera for shooting a field angleincluding maximum range (corresponding to the projection-allowable areaA11 described later) in which the projection section 30 can project animage on the screen SC, and performs shooting in accordance with thecontrol of the shooting control section 112, and then outputs the shotimage data. In other words, the imaging section 111 is set to be able toshoot the range including the entire projection-allowable area A11. Theimaging section 111 can always shoot the display surface, and can alsoperform shooting at only the necessary timing in accordance with thecontrol by the control section 170. The shooting control section 112controls the imaging section 111 to perform shooting in accordance withthe control of the control section 170. In the case in which the imagingsection 111 has a mechanism for adjusting the zoom magnification, thefocus, and the aperture in the shooting operation, the shooting controlsection 112 controls the mechanism to perform shooting on the conditionsset previously. After the shooting operation, the shooting controlsection 112 obtains the shot image data output by the imaging section111, and then outputs it to the position detection processing section113. The shot image data output from the imaging section 111 can also bethe data expressed in the form such as RGB or YUV, or can also be thedata representing only the luminance component. Further, the shootingcontrol section 112 can also output the shot image data, which is outputfrom the imaging section 111, to the position detection processingsection 113 without conversion, or can also output it to the positiondetection processing section 113 after performing the adjustment of theresolution or the conversion into a predetermined file format (e.g.,JPEG and BMP).

It should be noted that the imaging section 111 can also has aconfiguration capable of imaging the visible light, or a configurationcapable of imaging the non-visible light (e.g., infrared light). In thecase in which the imaging section 111 can image the non-visible light,it is possible to adopt, for example, the configuration in which the pen200 emits the non-visible light, and the imaging section 111 images thenon-visible light emitted from the pen 200, and the configuration inwhich the pen 200 includes a reflecting section capable of reflectingthe non-visible light, the non-visible light is projected from theprojector 100 toward the screen SC in accordance the control of thecontrol section 170, and then the non-visible light reflected by thereflecting section of the pen 200 is imaged by the imaging section 111.

The position detection processing section 113 analyzes the shot imagedata input from the shooting control section 112 to thereby extract theboundary between the outside of the actual projection area A12 and theactual projection area A12 and the image of the pen 200 from the shotimage data, and then identifies the indication position of the pen 200.The indication position of the pen 200 corresponds to, for example, aposition of the tip of the pen 200. The position detection processingsection 113 obtains the coordinate of the indication position thusdetected, in the actual projection area A12.

The coordinate calculation section 114 performs the calculation of thecoordinate based on the indication position of the pen 200 detected bythe position detection processing section 113 and the coordinateconversion parameters. Specifically, the coordinate calculation section114 obtains the coordinate of the indication position in the actualprojection area A12, detected by the position detection processingsection 113, and then outputs the control data representing thecoordinate thus calculated to the coordinate conversion section 120. Itshould be noted that in the following explanation, the data (thecoordinate information) representing the coordinate of the indicationposition of the pen 200 is referred to as “coordinate data,” or simplyas a “coordinate” in some cases.

The coordinate conversion section 120 converts the coordinate dataoutput by the position detection unit 110 into the coordinate datarepresenting the coordinate in the image data to be input by the PC 300to the projector 100. The coordinate output by the position detectionprocessing section 113 represents the coordinate detected based on theshot image data of the imaging section 111, and the coordinate can beexpressed by the coordinate in the coordinate axes virtually provided onthe screen SC. However, the correspondence relationship between thecoordinate on the screen SC and the coordinate on the shot image data isaffected by a variety of factors such as the distance between theprojector 100 and the screen SC, the zoom magnification in theprojection optical system 146, the installation angle of the projector100, and the distance between the imaging device 5 and the screen SC.Therefore, in the projector 100, the calibration is performed to therebyobtain the coordinate conversion parameters representing thecorrespondence relationship between the coordinate in the shot imagedata and the coordinate in the area on the screen SC to be the object ofthe calibration.

If the coordinate conversion parameters are obtained by the controlsection 170, the coordinate calculation section 114 performs theconversion of the coordinate based on the coordinate conversionparameters. The conversion process will be described later. Further, thecoordinate conversion section 120 converts the coordinate output fromthe coordinate calculation section 114 based on the image positioninformation described later, and then outputs the coordinate thusconverted into to the output section 150.

The output section 150 is connected to the PC 300, and outputs thecoordinate data, on which the conversion process of the coordinateconversion section 120 has been performed, to the PC 300. The outputsection 150 corresponds to the function device 11, the storage section12, and the supply section 15 shown in FIG. 1. In other words, theoutput section 150 is connected to the PC 300 in a manner compliant withthe USB standard, and has two interfaces. It should be noted that thestorage section 12 can also have a configuration of being formed of, forexample, a part of the storage section 180 instead of the configurationof being included in the output section 150. Further, the supply section15 can also be one of the functions of the control section 170.

Here, although the explanation will be presented assuming that the inputsection 160 and the output section 150 are functional blocks separatedfrom each other, it is obviously possible to integrate them into asingle interface. For example, it is also possible to realize both ofthe functions of the output section 150 and the input section 160 by asingle USB interface. Further, it is also possible for the outputsection 150 to be connected to the image processing section 133 providedto the image processing unit 130, and to output the coordinate, on whichthe conversion process of the coordinate conversion section 120 has beenperformed, to the image processing unit 130. The output destination ofthe output section 150 is controlled by the control section 170. Thecoordinate data (first coordinate data and second coordinate data)output by the output section 150 is output to the PC 300 as similar datato the coordinate data output by a pointing device such as a mouse, atrackball, a digitizer, or a pen tablet. For example, it is possible toassign holding down operations of a first switch 211 and a second switch212 provided to the pen 200 to either one of a so-called right clickoperation and left click operation of a mouse and the other thereof,respectively.

Further, if the PC 300 treats the coordinate data output from the outputsection 150 equivalently to the coordinate data output bygeneral-purpose pointing devices, a general-purpose device driverprogram corresponding to such general-purpose pointing devices can beused. In general, since such general-purpose device driver programs arepreviously installed as a part of the OS of the PC 300, it is notnecessary to further install a device driver program in the case ofusing the general-purpose device driver program. Further, since thegeneral-purpose device driver program is used, it is not necessary toprepare a dedicated device driver program on the one hand, but theinformation which can be exchanged between the projector 100 and the PC300 is limited to the range determined by the specification of thegeneral-purpose device driver program on the other hand.

Further, it is also possible to prepare the dedicated device driverprogram corresponding to the projector 100, and then use the devicedriver program after installing it into the PC 300. In this case, thededicated device driver program is required on the one hand, and theinformation which can be exchanged between the projector 100 and the PC300 can arbitrarily be set in accordance with the specification of thededicated device driver program.

FIG. 4 is a block diagram showing a configuration of the PC 300. Asshown in FIG. 4, the PC 300 is provided with a CPU 310 for executing acontrol program to centrally control each part of the PC 300, a ROM 320storing a basic control program to be executed by the CPU 310 and thedata related to the program, a RAM 330 for temporarily storing theprograms to be executed by the CPU 310 and the data, a storage section340 for storing the programs and the data in a non-volatile manner, aninput section 350 for detecting input operations and outputting data andoperation signals representing the input content to the CPU 310, adisplay section 360 for outputting display data for displaying theprocessing result or the like by the CPU 310, and an external I/F 370for transmitting/receiving the data and so on to/from an externaldevice, and these sections are connected to each other through a bus.

The input section 350 has an input I/F 380 having a connector and apower supply circuit, and an input device 381 is connected to the inputI/F 380. The input I/F 380 corresponds to the host controller 31 shownin FIG. 1, and the input device 381 corresponds to, for example, akeyboard or a pointing device such as a mouse or a digitizer.

A USB cable coupled to the projector 100 is connected to the input I/F380, and the coordinate of the indication position by the pen 200 isinput from the projector 100 to the input I/F 380. Here, the coordinatedata output by the output section 150 of the projector 100 is input tothe input I/F 380 as the similar data to the coordinate data output by apointing device such as a mouse, a trackball, a digitizer, or a pentablet. Therefore, the PC 300 can process the coordinate data input fromthe projector 100 as an input signal from the input device, and canperform an operation of, for example, performing the translation of amouse cursor or a pointer based on the coordinate data.

The display section 360 has an image output I/F 390 provided with aconnector for outputting the image signal, a monitor 391 and an imagesignal cable (not shown) to be coupled to the projector 100 areconnected to the image output I/F 390. The image output I/F 390 isprovided with, for example, a plurality of VGA (Video Graphics Array)terminals for outputting an analog video signal, DVI interfaces, USBinterfaces, and LAN interfaces for outputting a digital video signal,S-video terminals for outputting a video signal such as NTSC, PAL, orSECAM, RCA terminals for outputting a composite video signal,D-terminals for outputting a component video signal, and HDMI connectorscompliant with the HDMI standard, and the monitor 391 and the projector100 are connected respectively to these connectors. Further, there canalso be adopted a configuration in which the image output I/F 390 isprovided with a DisplayPort developed by VESA, and specifically, therecan also be adopted a configuration in which the image output I/F 390 isprovided with the DisplayPort connector or the Mini-DisplayPortconnector and an interface circuit compliant with the DisplayPortstandard. In this case, the PC 300 can output the digital video signalto the projector 100, the monitor 391, or other devices via theDisplayPort. It should be noted that it is also possible for the imageoutput I/F 390 to perform transmission/reception of the image signalusing wired communication, or to perform transmission/reception of theimage signal using wireless communication.

The storage section 340 stores a display control program to be executedby the CPU 310, and image data to be output when executing the displaycontrol program. When executing the display control program, the CPU 310performs a process of transmitting the image data to the projector 100.In this process, the CPU 310 reproduces the image data, and at the sametime makes the display section 360 generate the image signal with apredetermined display resolution and then output it to the image outputI/F 390. Here, the display section 360 outputs the analog image signalto a connector for outputting an analog signal, and outputs the digitalimage data to a connector for outputting digital data.

Further, the CPU 310 generates an image for displaying the pointer P1(FIG. 2) at a position corresponding to the coordinate corresponding toan operation of the pen 200 when the coordinate is input from the inputsection 350 during the execution of the display control program. Then,the CPU 310 generates the image data having the pointer P1 superimposedon the image data presently reproduced, and then outputs the image datafrom the image output I/F 390 to the projector 100. Further, asdescribed later, the CPU 310 performs setting and control with respectto the display in the handwriting area. In other words, in the presentembodiment the control section 310 realizes a function corresponding tothe execution section 32 shown in FIG. 1.

As described above, in the display system 1, the PC 300 performs thefunction of drawing the pointer P1 superimposed on the image data outputby the PC 300 to the projector 100.

FIG. 5 is a diagram showing an example of an appearance of the pen 200.The pen 200 is provided with the first switch 211 and the second switch212. The first switch 211 is disposed on the tip of the pen 200, and isa switch configured so that the user can hold down the switch bypressing the pen 200 against the screen SC. On the other hand, thesecond switch 212 is disposed on the shaft of the pen 200 so as to beable to be held down. The first switch 211 and the second switch 212each can function like a button of a mouse. Further, the tip of thefirst switch 211 is provided with an opening, and is configured so thatlight (visible light or non-visible light) is emitted through theopening.

FIG. 6 is a block diagram showing a configuration of the pen 200. Thepen 200 is provided with an operation section 210 having the firstswitch 211 and the second switch 212, and for outputting an operationsignal corresponding to the operation of the user, an irradiationcontrol section 220 for controlling the irradiation condition of thelight in accordance with the operation signal from the operation section210, and an irradiation section 230 for irradiating an object with thelight in accordance with the control by the irradiation control section220. The irradiation control section 220 varies the irradiation pattern(e.g., the period of lighting or extinction, the intervals, theintensity, and the wavelength) of the light in accordance with theoperation of the user. The irradiation section 230 has a light sourcesuch as an LED or a laser diode. The light with which the irradiationsection 230 irradiates an object can be either of visible light andnon-visible light (e.g., infrared light).

In the present embodiment, the number of the pens 200 existingcorresponds to the number of the users, namely a plurality of the pens200 exists. In the present embodiment, each of the pens 200 isconfigured to be optically discriminated from each other. The pens 200can be configured so as to be discriminated from each other by makingthe irradiation patterns of the light different from each other.Further, the pens 200 can also be discriminated by making thewavelengths (i.e., the colors) of the light, with which the object isirradiated, different from each other, or can also be discriminated byproviding images such as barcodes or ID to the housing of the pens 200with printing or labels, and then analyzing the shot image data obtainedby shooting the images. Such image analysis can be performed by theposition detection processing section 113.

Operation Example of Calibration Etc.

FIGS. 7A and 7B are diagrams showing an example of projecting an imageon a screen SC by the projector 100, wherein FIG. 7A shows a state ofprojecting the pointer P1 in accordance with the indication position ofthe pen 200, and FIG. 7B shows the state in which a hand-written imageH1 is drawn in accordance with the indication position.

In this example, if the display image is projected using the entireliquid crystal panel provided to the light modulation device 145, theimage is formed in the projection-allowable area A11 indicated by thedashed-two dotted line in FIG. 7A. Since the keystone distortion isgenerated in the projection-allowable area A11 as shown in FIG. 7Aexcept the case in which the projector 100 is located right in front ofthe screen SC, the projector 100 performs the keystone correction due tothe function of the display control section 132. After performing thekeystone correction, the display image is projected in the actualprojection area A12 as a part of the projection-allowable area A11. Theactual projection area A12 is normally set so as to have a rectangularshape on the screen SC, and have the maximum size within theprojection-allowable area A11. Specifically, the actual projection areaA12 is determined based on the resolution of the liquid crystal panel ofthe light modulation device 145 and the level of the keystonedistortion, and is not necessarily required to have the maximum size. Itshould be noted that if the keystone distortion does not occur in theimage projected from the projector 100, execution of the keystonecorrection is not required. In this case, the actual projection area A12coincides with the projection-allowable area A11.

The control section 170 of the projector 100 performs the calibration tothe actual projection area A12 on which the keystone correction has beenperformed. In the calibration, the control section 170 controls theimage processing section 133 to draw a predetermined image forcalibration. In the state in which the image for calibration isprojected on the screen SC, the position detection unit 110 shoots thescreen SC under the control of the control section 170. The image forcalibration is, for example, an image with some dots arranged on thewhite background, and is stored in advance in the storage section 180and so on. It should be noted that the image for calibration is notnecessarily required to be stored in the storage section 180 or thelike, it is also possible to adopt the configuration in which thecontrol section 170 generates the image for calibration on acase-by-case basis every time necessity of the execution of thecalibration arises and the calibration is executed.

The area in the screen SC to be the object of the calibration can be theentire actual projection area A12 or apart of the actual projection areaA12. As the case of setting a part of the actual projection area A12 tothe object of the calibration, there can be cited the case in which thedisplay is performed so that the vertical width of the display image ofthe projector 100 coincides with the vertical width of the screen SCwhile the aspect ratio of the image to be displayed by the projector 100and the aspect ratio of the screen SC are different from each other(e.g., the display resolution of the projector 100 is WXGA (with theaspect ratio of 15:9), while the aspect ratio of the screen SC is 4:3).In this case, it is possible to take the area included in the screen SCout of the actual projection area A12 of the projector 100 as the objectof the calibration, and exclude the other area from the object of thecalibration.

The control section 170 detects the outline of the display image in theshot image data, namely the boundary between the outside of the actualprojection area A12 and the actual projection area A12, and the dots inthe shot image data, and then identifies the correspondence relationshipbetween positions in the shooting range (field angle) of the positiondetection unit 110, namely the positions in the shot image, andpositions on the actual projection area A12. The control section 170obtains the coordinate conversion parameters to be used by thecoordinate calculation section 114 as described later based on thecorrespondence relationship between the positions on the shot image andthe positions on the actual projection area A12 identified by thecalibration. The coordinate conversion parameters include, for example,the data for making the coordinate on the image drawn by the imageprocessing section 133 and the coordinate obtained on the shot imagedata correspond to each other. The coordinate calculation section 114can convert the coordinate obtained on the shot image data into thecoordinate on the image drawn by the image processing section 133 basedon this coordinate conversion parameter. The coordinate calculationprocess is performed based on this coordinate conversion parameter.

Since the calibration is performed by the control section 170 executinga calibration program (not shown) stored in the storage section 180, itis not required to install and execute the calibration program in the PC300. Further, the calibration can be the process automatically performedby the control section 170 based on the shot image data, or can be theprocess requiring an operation of the user to the image for calibrationprojected. Further, it is also possible for the calibration to beperformed by using both of these processes. As the operation by the userto the image for calibration, there can be cited, for example, anoperation of the user to indicate the dot included in the image forcalibration thus projected with the pen 200.

The position detection unit 110 provided to the projector 100 performsthe shooting in the state in which the image is projected in the actualprojection area A12, virtually sets the Cartesian coordinate system inthe shot image taking either one of the vertexes of the actualprojection area A12 as the origin as indicated by the dotted arrows inthe drawings, and obtains the coordinate of the tip position of the pen200 in the coordinate system. The Cartesian coordinate system is setbased on the coordinate conversion parameters, which can be obtained bythe calibration described above. Subsequently, when the coordinate ofthe tip of the pen 200 in the image data displayed in the actualprojection area A12 is obtained by the coordinate conversion section120, the pointer P1 and the menu bar M1 shown in FIG. 7A, for example,are displayed in accordance with the coordinate. The pointer P1 is drawnas a symbol indicating the tip position of the pen 200. The pointer P1can be an image of a simple dot, or can also be an image of a cross oran arrow. Further, the menu bar M1 is a graphical user interface (GUI)widget, which can be operated by the pen 200, and it becomes possiblefor the user to perform operations related to the operation of theprojector 100 by indicating the buttons disposed in the menu bar M1 withthe pen 200. Here, the operations which can be performed by the menu barM1 include, for example, drawing of a symbol such as a line, storing,deleting, and copying of a hand-written image drawn, transfer of thehand-written image drawn, an operation (undo) of undoing the lastoperation, and an operation (redo) of redoing the operation undone bythe undo operation.

As a specific example, by moving the pen 200 from the position shown inFIG. 7A to the position in FIG. 7B, the hand-written image H1 is drawnalong the trajectory of the tip of the pen 200. The hand-written imageH1 is an image, which the PC 300 makes the projector 100 draw inaccordance with the coordinate data representing the indication positionof the pen 200 similarly to, for example, the pointer P1 and the menubar M1. Further, it is possible for the user to set the color and thethickness of the line of the hand-written image H1 by indicating themenu bar M1 before drawing the hand-written image H1.

Further, in the menu bar M1, there can be disposed a button forcontrolling the slide show display for sequentially displaying aplurality of images (e.g., image data stored by an external storagedevice such as a USB flash memory connected to, for example, theexternal I/F 370) which can externally be supplied, a button forexecuting setting (e.g., change in the aspect ratio and change in thecolor mode) related to the function itself of the projector 100, and soon. In other words, the operations performed by the menu bar M1 caninclude those having no direct relation with drawing of a hand-writtenimage. In the case in which the indication position of the pen 200 isoutput from the coordinate conversion section 120, the control section170 obtains the coordinate to identify the button indicated in the menubar M1, and then executes the operation corresponding to the indicationoperation.

FIGS. 8A and 8B are explanatory diagrams showing how the projector 100performs the process of detecting the coordinate of the indicationposition, and then converting it into the coordinate in the image data,wherein FIG. 8A shows the initial state of the series of operations, andFIG. 8B shows the state in which the resolution of the display image ischanged from the state shown in FIG. 8A. It should be noted that in thefollowing explanation, there will be explained the case in which nokeystone distortion occurs in the image projected by the projector 100,and the image displayed in the entire modulation area of the lightmodulation device 145 is displayed in the actual projection area A12. Inthis case, the actual projection area A12 coincides with theprojection-allowable area A11, and the resolution of the image displayedin the actual projection area A12 is equal to the resolution of theliquid crystal panel of the light modulation device 145.

In the example shown in FIG. 8A, the resolution of the liquid crystalpanel of the light modulation device 145 and the resolution of the imagedisplayed in the actual projection area A12 are both 1280×800 dots.Further, the resolution of the image data input from the PC 300 is also1280×800 dots. Therefore, in the actual projection area A12, the displayimage Im11 with the resolution of 1280×800 dots is displayed. Theposition detection unit 110 sets the X-Y Cartesian coordinate systemtaking the upper left corner of the actual projection area A12 as theorigin, the rightward direction as the X-axis positive direction, andthe downward direction as the Y-axis positive direction, and detects thecoordinate (X1 n, Y1 n) of the indication position of the pen 200 in theactual projection area A12. The coordinate data output by the coordinatecalculation section 114 represents the coordinate (X1 n, Y1 n) of theindication position.

The coordinate (X1 n, Y1 n) of the indication position is a coordinate(normalized coordinate) normalized in the actual projection area A12.Specifically, the coordinate X1 n of the indication position in theX-axis direction represents the ratio of the length WP1 from the leftside of the actual projection area A12 to the indication position withrespect to the lateral width W1 of the actual projection area A12.Further, the coordinate Y1 n of the indication position in the Y-axisdirection represents the ratio of the length HP1 from the upper side ofthe actual projection area A12 to the indication position with respectto the vertical width H1 of the actual projection area A12. It should benoted here that the values W1, WP1, H1, and HP1 are expressed with thenumber of pixels.

In this case, the coordinate (X1 n, Y1 n) is calculated by the formulas1, 2 described below.X1n=WP1÷W1  (1)Y1n=HP1÷H1  (2)

For example, in the example shown in FIG. 8A, WP1=400 and HP1=300 areassumed. Since the resolution of the display image Im11 is 1280×800dots, W1=1280 and H1=800 are true. Therefore, the expressions of X1n=400÷1280≈0.313 and Y1 n=300÷800=0.375 can be obtained. Further, inthis case, the coordinates of the upper left vertex of the actualprojection area A12, the upper right vertex thereof, the lower leftvertex thereof, and the lower right vertex thereof are expressed as (0,0), (1, 0), (0, 1), and (1, 1), respectively. It should be noted that inthe state shown in FIG. 8A since the actual projection area A12 and thearea in which the display image Im11 is displayed coincide with eachother, the coordinates (X1 n, Y1 n) can also be regarded as thecoordinates normalized in the display image Im11.

Here, if the image data input from the PC 300 is switched to the displayimage Im12 with the resolution of 1024×768 dots, the projector 100scales the image data so that the vertical resolution (768 dots) of theimage data is increased to the vertical resolution (800 dots) of theliquid crystal panel. Since the scaling is performed in both of thevertical direction and the horizontal direction in a similar manner, thehorizontal resolution (1024 dots) of the image data is scaled to1024×(800÷768)≈1066 dots. As a result, as shown in FIG. 8B, the displayimage Im12 with the resolution of 1066×800 dots is projected on thescreen SC. Since the aspect ratio and the resolution of the displayimage Im12 are different from the aspect ratio and the resolution of thedisplay image Im11, the area in which the display image Im12 isprojected does not coincide with the actual projection area A12. In theexample shown in FIG. 8B, the area in which the display image Im12 isprojected is smaller than the actual projection area A12. Further, theprojector 100 changes the position thereof so that the image thus scaledis displayed at a position near to the center as much as possible.Therefore, in the actual projection area A12, the position of the upperleft vertex of the display image Im11 and the position of the upper leftvertex of the display image Im12 do not coincide with each other.

Here, as shown in FIGS. 8A and 8B, when switching the display image Im11to the display image Im12 in the state in which the pen 200 on thescreen SC is fixed, the relative position between the indicationposition and the image displayed varies although the indication positionitself is not moved. Therefore, the coordinate (X1 n, Y1 n) of theindication position normalized taking the upper left vertex of thedisplay image Im11 as the origin and the coordinate (X2 n, Y2 n) of theindication position normalized taking the upper left vertex of thedisplay image Im12 as the origin are different from each other.Therefore, if the pointer P1 is displayed based on the coordinate (X1 n,Y1 n) of the indication position in the actual projection area A12,which the position detection unit 110 has calculated based on the shotimage data of the imaging section 111, the pointer P1 is shifted fromthe actual indication position.

In the example shown in FIG. 8B, for example, the upper left vertex ofthe display image Im12 is located at a position shifted 107(=(1280−1066)+2) pixels rightward from the upper left vertex of thedisplay image Im11. Therefore, defining that the length from the leftside of the display image Im12 to the indication position is WP2, andthe length from the upper side of the display image Im12 to theindication position is HP2, WP2=WP1−107=400−107=293 and HP2=HP1=300 areobtained. Further, since the resolution of the display image Im12 is1066×800 dots, the lateral width W2 and the vertical width H2 of thedisplay image Im12 are W2=1066 and H2=800, respectively. Therefore, thecoordinate (X2 n, Y2 n) of the indication position normalized taking theupper left vertex of the display image Im12 as the origin is expressedas X2 n=(400−107)÷1066≈0.275, Y2 n=300÷800=0.375. As described above, X1n≠X2 n is resulted, and if the resolution of the display image ischanged, the normalized coordinate of the indication position is alsochanged.

Therefore, if the pointer P1 is displayed at the coordinate (X1 n, Y1n)=(0.313, 0.375) in the coordinate system taking the upper left cornerof the display image Im12 having been changed as the origin, a pointerP1 a is displayed at the position separate from the tip of the pen 200.This is because the PC 300 performs the drawing taking the upper left ofthe image as the origin based on the normalized coordinate output fromthe position detection unit 110 when drawing the pointer P1. Asdescribed above, since the coordinate obtained taking the actualprojection area A12 as a reference is affected by the resolution of thedisplay image, it is not achievable for the PC 300 to directly use thecoordinate calculated by the position detection unit 110 for the displayof the pointer P1.

Therefore, the projector 100 performs the process of converting thecoordinate (X1 n, Y1 n) of the indication position calculated by thecoordinate calculation section 114 of the position detection unit 110into the coordinate (X2 n, Y2 n) of the indication position in thedisplay image presently displayed using the coordinate conversionsection 120 so as to be able to cope with the case in which theresolution of the display image has changed.

The coordinate conversion section 120 converts the coordinate (X1 n, Y1n) into the coordinate (X2 n, Y2 n) based on the image positioninformation input from the image processing section 133. The imageposition information is the information related to the configuration ofthe image in the modulation area of the light modulation device 145.Further, the modulation area of the light modulation device 145corresponds to the actual projection area A12 on the screen SC.Therefore, the image position information represents the position(configuration) of the display image with respect to the actualprojection area A12. In the present embodiment, the image positioninformation represents the position (configuration) and the size of thedisplay image with respect to the actual projection area A12. Based onthe image position information, the coordinate conversion section 120obtains the coordinate of the indication position in the display image.For example, in the example shown in FIGS. 8A and 8B, the values W1, H1,W2, and H2 correspond to the image position information. Further, thecoordinate (XO1, YO1)=(0, 0) of the upper left end of the display imageIm11 and the coordinate (XO2, YO2)=(107, 0) of the upper left end of thedisplay image Im12 also correspond to the image position information. Itshould be noted that the coordinates XO1, YO1, XO2, and YO2 are not thenormalized coordinates, but are those representing the positions of theupper left vertex of the display image with the number of pixels takingthe upper left vertex (or the upper left vertex of the modulation areaof the light modulation device 145) of the actual projection area A12 asthe origin in the actual projection area A12 (or the modulation area ofthe light modulation area 145). In the example shown in FIGS. 8A and 8B,the image position information of the display image Im11 (XO1, YO1, W1,H1)=(0, 0, 1280, 800) is obtained, and the image position information ofthe display image Im12 (XO2, YO2, W2, H2)=(107, 0, 1166, 800) isobtained.

The coordinate (X2 n, Y2 n) calculated by the coordinate calculationsection 120 can be used as the information for identifying the positionin the image data when the PC 300 draws the pointer P1, the menu bar M1,or the hand-written image H1 in the image data as the processing object.Therefore, the pointer P1, the menu bar M1, and the hand-written imageH1 can accurately be drawn in accordance with the indication position bythe pen 200 without being affected by the resolution of the displayimage, the zooming ratio, and so on.

Incidentally, the position and the size of the display image displayedin the actual projection area A12 are affected by the resolution and thedisplay position of the display image. For example, in the case in whichthe projector 100 performs the process of changing the projection statesuch as change in the display resolution, change in the aspect ratio,zooming, change (translation) in the display position of the image, ormulti-screen display process in accordance with an operation by theoperation section 190, or a control signal transmitted from the PC 300,the image position information is also changed. As described above, theimage position information is the information related to theconfiguration of the image placement area (the area in which the displayimages Im11, Im12 are projected (displayed)) with respect to the actualprojection area A12. In other words, the image position information isthe information representing the position (configuration) of the displayimage with respect to the actual projection area A12 (thedisplay-allowable area). Further, the image position information alsovaries in the case (e.g., the case in which the setting with respect tothe resolution is changed in the PC 300) in which the display resolutionof the PC 300 is varied, and the resolution of the image data output bythe PC 300 to the projector 100 is varied. It should be noted that the“multi-screen display process” denotes the process of dividing theactual projection area A12 of the projector 100 into a plurality ofareas, and displaying the images different from each other respectivelyinput from a plurality of image supply devices in the respective areas.

The coordinate conversion section 120 obtains the information from thecontrol section 170 and the display control section 132 to update theimage position information, and then converts the coordinate based onthe image position information thus updated every time the projectionstate (the display state) of the display image by the projection section30 is varied. The image position information is updated at, for example,the timings cited below.

The control section 170 has detected the input of the image data fromthe PC 300.

The control section 170 has detected the change in the information(e.g., the resolution of the image) related to the image data input fromthe PC 300.

The resolution of the image data has changed in the projector 100.

The aspect ratio of the image data has changed in the projector 100.

The digital zoom function of expanding/contracting the image to be drawnby the light modulation device 145 using the image processing of theimage data to be projected has been executed or terminated.

The display position of the display image with respect to the actualprojection area A12 has been changed.

The image has been enlarged by the digital zoom function describedabove, and then the function of changing the display position of theimage using the image processing has been executed or terminated.

The Tele/Wide function for expanding/contracting the projection size ofthe whole including the image drawn by the light modulation device 145and the background, namely the entire actual projection area A12, byperforming the image processing on the image data has been executed orterminated.

The image has been contracted by the digital zoom function describedabove, and then the picture shift function of changing the displayposition of the image using the image processing has been executed orterminated.

The simultaneous display of a plurality of images has been executed orterminated.

The output destination to which the coordinate is output from thecoordinate conversion section 120 has been changed from the imageprocessing unit 130 to the PC 300 (the output section 150) or viceversa.

The change in the resolution, the change in the aspect ratio, and theexecution and termination of the variety of functions are all executedby the image processing unit 130 under the control of the controlsection 170. It should be noted that the timings cited above are nothingmore than examples, and it is obviously possible to update the imageposition information at other timings.

FIG. 9 is a flowchart showing the operation of the projector 100, and inparticular showing the operation of detecting the indication position bythe pen 200 and then outputting the coordinate of the indicationposition.

After the start-up of the projector 100 or in the case in which displayof the pointer P1 or the menu bar M1 is instructed by the operation ofthe operation section 190, the operation shown in FIG. 9 is repeatedlyexecuted at regular intervals until the projection is terminated.

Firstly, whether or not the calibration is necessary is determined (stepS11). This determination can also be performed based on the instructionof the user expressing whether or not the calibration is necessary, orit is also possible that the control section 170 automaticallydetermines whether or not the calibration is necessary to be performed,and the determination is performed automatically based on thedetermination result. If the calibration is necessary (YES in the stepS11), the calibration is performed (step S12) as explained withreference to FIG. 7A. Specifically, by making the image processingsection 133 draw the image for calibration, making the positiondetection unit 110 perform shooting in the state in which the image forcalibration is projected, and then detecting the outline of the actualprojection area A12 in the shot image data thus obtained and thecharacteristic points (e.g., the dots) included in the image forcalibration, the correspondence relationship between the image drawn bythe image processing section 133 and the shot image data is obtained. Itshould be noted that it is sufficient to perform the calibration onceafter starting the use of the projector 100, and it is not necessary toperform the calibration once again unless a specific event occurs. It isnecessary to newly perform the calibration in, for example, the cases 1through 3 below.

1. The keystone correction has been performed.

2. The installation conditions of the projector 100 have changed. Forexample, the relative position (including the orientation) of theprojector 100 with respect to the screen SC has changed.

3. Optical conditions have changed. For example, the state of focus orzoom of the projection optical system 146 has changed. The optical axisof the projection optical system 146 or the imaging section 111 isshifted due to temporal change thereof and so on.

If any of these events occurs, since the correspondence relationshipbetween the position on the shot image data and the position on theimage drawn by the image processing section 133 in the initial state,which forms the basis for the coordinate conversion section 120 tocalculate the coordinate, is changed (in other words, the coordinateconversion parameters are varied), it is necessary to newly perform thecalibration. In contrast, since it is not necessary to perform thecalibration once again unless any of these events occurs, if the eventsdescribed above have not occurred during the period from when theprojector 100 is used previously to when the projector 100 is used thistime, the coordinate conversion parameters obtained in the previouscalibration can also be reused without newly performing the calibration.As the method for the control section 170 to determine whether or notthe calibration is necessary to be performed, there can be cited, forexample, a method of making the determination based on the presence orabsence of the operation of the switch instructing the execution of thekeystone correction in the operation section 190, and a method ofproviding a sensor for detecting the tilt and the movement to theprojector 100, and making the determination based on the variation inthe detection value of the sensor. Further, it is also possible for thecontrol section 170 to automatically perform the calibration if thefocus adjustment or the zoom adjustment in the projection optical system146 is performed. Further, it is also possible to provide a dedicatedswitch to the operation section 190 or the remote controller so that theuser figures out the change in the installation position of theprojector 100 and the optical conditions, and can perform the operationof instructing the execution of the calibration.

When the shooting control section 112 makes the imaging section 111shoot the range including the actual projection area A12 under thecontrol of the control section 170, the position detection processingsection 113 obtains (step S13) the shot image data, and then detects(step S14) the indication position of the pen 200 based on the shotimage data. Subsequently, the coordinate calculation section 114calculates (step S15) the coordinate of the indication position detectedby the position detection processing section 113. The coordinatecalculated in the step S15 is the coordinate in the actual projectionarea A12, and corresponds to the coordinate (X1 n, Y1 n) explained withreference to FIG. 8A.

The coordinate conversion section 120 determines (step S16) whether ornot the update of the image position information is necessary, and thenobtains the information from the control section 170 and the displaycontrol section 132, and updates (step S17) the image positioninformation if the update is necessary. The timing of the process of thestep S17 is not limited to the posterior stage of the step S15, but theprocess of the step S17 can also be performed at the timings describedabove as an example.

Subsequently, the coordinate conversion section 120 performs (step S18)the process for converting the coordinate calculated by the coordinatecalculation section 114 into the coordinate in the image data of thedisplay image. The coordinate thus converted corresponds to thecoordinate (X2 n, Y2 n) explained with reference to FIG. 8B.

The coordinate conversion section 120 outputs (step S19) the coordinatethus converted to the PC 300, and then terminates the present process.

As described above, in the display system 1, the projector 100 isprovided with the projection unit 140 for displaying the display imageon the screen SC based on the image data, the position detectionprocessing section 113 for detecting the indication position withrespect to the display image on the screen SC, the coordinatecalculation section 114 for calculating first coordinate information,which is the coordinate of the indication position in thedisplay-allowable area (e.g., the actual projection area A12) in thescreen SC, the coordinate conversion section 120 for converting thefirst coordinate information calculated by the coordinate calculationsection 114 into second coordinate information, which is the coordinatein the image data, and the output section 150 for outputting the secondcoordinate information obtained by the coordinate conversion section120, and outputs the coordinate of the indication position by the pen200 as the coordinate in the image data, and therefore, it is possibleto identify the relative position between the indication position andthe image data in the PC 300 and so on, which use the coordinate thusoutput, without being affected by the display configuration such as thedisplay resolution or the size of the display area. Since it is notnecessary to make the image data itself and the indication positiondirectly correspond to each other in the process of obtaining thecoordinate of the indication position in the image data, it is notnecessary to perform the calibration even if the change in size and soon of the image data occurs. Therefore, the execution frequency of thecalibration can be reduced. Thus, enhancement of the convenience of theprojector 100 can be achieved. Further, since it is not necessary toexecute the program for the calibration on the PC 300 side, the load tothe user unfamiliar with the operation of the PC 300 can be reduced.

Further, since the coordinate conversion section 120 converts the firstcoordinate information calculated by the coordinate calculation section114 into the second coordinate information based on the image positioninformation, which is the information representing the position of thedisplay image with respect to the display-allowable area, even if theimage position information, which is the information representing theposition of the display image with respect to the display-allowablearea, is varied, the coordinate conversion section 120 can accuratelyconvert the coordinate of the indication position by the pen 200, andthen output the result.

Further, the coordinate conversion section 120 converts the firstcoordinate information calculated by the coordinate calculation section114 into the second coordinate information based on the resolution ofthe image data. For example, the coordinate conversion section 120performs the conversion of the coordinate using the image positioninformation reflecting the display resolution of the projection section30 and the resolution of the image data. Thus, the coordinate of theindication position can correctly be converted and then output even ifthe resolution of the image data varies.

Further, the position detection unit 110 detects the position of the pen200 on the screen SC based on the shot image shot by the imaging section111 to thereby detect the indication position in the actual projectionarea A12, and can therefore detect the indication position promptly.

Operation Example Related to Change in Configuration Information

FIG. 10 is a flowchart showing a process executed by the projector 100in the case of displaying a hand-written image. It should be noted herethat it is assumed that a single user uses a single pen 200. As shown inFIG. 10, the control section 170 of the projector 100 firstly determines(step S21) whether or not the indication position has been detected. Thecontrol section 170 skips (omits) the process of the steps S22, S23 ifthe indication position has not been detected on the other hand, orgenerates the coordinate data, and then supplies it to the outputsection 150 to thereby transmit (step S22) the coordinate data to the PC300 if the indication position has been detected on the other hand.

On this occasion, the control section 170 makes assignment topredetermined one of the interfaces (the first interface 11 a and thesecond interface 11 b) and then supplies the coordinate data. Theassignment is described as the configuration information, and has beendetermined when executing the enumeration. Here, it is assumed that thecontrol section 170 assigns the coordinate data to the first interface11 a, and the configuration information of the mouse is used as theconfiguration information at this moment.

On the other hand, in the PC 300, the CPU 310 identifies the indicationposition based on the coordinate data, and then generates the image datafor displaying the hand-written image corresponding to the indicationposition thus identified. On this occasion, the CPU 310 recognizes thatthe coordinate data is indicated by a mouse based on the configurationinformation received from the projector 100. It should be noted that thecoordinate data includes the information representing the holding-downstate of the first switch 211 and the second switch 212 in addition tothe coordinate of the indication position. When the image data isgenerated, the PC 300 supplies the projector 100 with the image datathus generated. The control section 170 makes the projection unit 140display the hand-written image corresponding to the image data tothereby update (step S23) the image on the display surface.

Then, the control section 170 determines (step S24) whether or not theuser has performed the operation of changing the interface.Specifically, the control section 170 determines whether or not theoperation of displaying the OSD image for changing the interface hasbeen performed, and the operation of changing the interface has beenperformed via the OSD image thus displayed. The control section 170changes (step S25) the interface on the one hand if the such anoperation has performed, or otherwise skips the process of the step S25,and then performs the process on and after the step S21 again in arepeated manner.

FIG. 11 is a diagram for exemplifying an OSD image. The OSD image O1 isan OSD image to be displayed in the case in which the number of the pens200 is one (i.e., the number of the users is one). Check boxes C11, C12are images respectively showing whether or not the pen 200 is made tofunction as a mouse, and whether or not the pen 200 is made to functionas a digitizer, and a check mark is displayed on either one of the checkboxes, which is selected by the user (or set in the initial state).Specifically, in this example, the function of a mouse is assigned tothe pen 200.

It is possible for the user to change the assignment of the function tothe pen 200 by operating the operation section 190 or the remotecontroller, or by indicating either one of the check boxes C11, C12 withthe pen 200. For example, if the user selects the check box C12 in thestate in which the OSD image O1 shown in FIG. 11 is displayed, thefunction assigned to the pen 200 is switched from the function of amouse to the function of a digitizer. Simultaneously, the check mark isdisplayed in the check box C12, and the check mark in the check boxdisappears.

If the class of the device is switched in such a manner, the informationsupplied from the projector 100 to the PC 300 also varies. For example,in the case in which the user uses the pen 200 as a digitizer, there issupplied the information, which is not supplied in the case in which theuser uses the pen 200 as a mouse. There can be cited an example in whichalthough a value (In Range) representing whether or not the pen 200exists in a detectable area is supplied together with the coordinatedata in the case in which the user uses the pen 200 as a digitizer, itis not required to supply such a value (it should be noted that in thepresent embodiment the state in which the pen 200 exists in thedetectable area denotes the state in which the position detection unit110 detects the indication position) in the case in which the user usesthe pen 200 as a mouse. Further, the holding-down state of the firstswitch 211 and the second switch 212 can also be recognized as theinformation different between the case in which the pen 200 functions asa mouse and the case in which the pen 200 functions as a digitizer.

It should be noted that the selection method of the function to beassigned to the pen 200 is not limited to the example shown in FIG. 11,but can also be, for example, a method of selecting the function using apull-down menu or the like. Further, it is obviously possible to switchthe assignment of the function to the pen 200 from the function of adigitizer to the function of a mouse in a similar manner to the exampledescribed above.

In this case, as the method of changing the interface, there can becited the two methods described below. The first method is a method ofchanging the configuration information assigned to the interface fromthe configuration information of a mouse to the configurationinformation of a digitizer (or vice versa). In contrast, the secondmethod is a method of changing the interface itself related to thesupply of the coordinate data, and is not the method of changing theconfiguration information assigned to the interface. In the case of thesecond method, the correspondence relationship between the interface andthe device is determined in advance in such a manner, for example, thatthe first interface 11 a is assigned to a mouse while the secondinterface 11 b is assigned to a digitizer, and the control section 170performs the control so as to supply the coordinate data via theinterface assigned to the device of the class selected by the user.

It should be noted that in the case of the first method it is requiredto once cut the USB connection between the PC 300 and the projector 100,and then reconnect them to each other. Cutting and connecting mentionedhere are realized by pulling up or pulling down the D+ line out of thesignal lines in the USB standard. Further, substantially the same thingcan be realized by connecting or cutting the Vbus line. The controlsection 170 transmits the configuration information thus changed in thereconnection after cutting.

In contrast, in the case of the second method, cutting of the USBconnection is not necessary.

Further, the change of the interface is also possible in the case ofusing two pens 200. If the case of using a single pen 200 and the caseof using two pens 200 are both possible, it is possible for the controlsection 170 to identify the number of the pens 200 (or the number of theusers), and then display the OSD image corresponding to the number thusidentified.

FIGS. 12 and 13 are diagrams showing other examples of the OSD image.The OSD image O2 shown in FIG. 12 is an OSD image for selecting thenumber of the users, and includes check boxes C21, C22. Further, the OSDimage O3 shown in FIG. 13 is an OSD image for respectively selecting theconfiguration information corresponding to the two users (i.e., two pens200), and the configuration information for one (user 1) of the users isselected using the check boxes C31, C32, and the configurationinformation for the other (user 2) of the users is selected using thecheck boxes C33, C34.

As described hereinabove, it is possible for the display system 1 toswitch the class of the device in accordance with the operation of theuser in such a manner that the pen 200 is made to function as a mouse,or to function as a digitizer. Thus, it becomes possible for the user touse the single pen 200 selectively for each of the purposes thereof.

Further, according to the display system 1, it is possible for the userhim or herself to select the format of the data supplied from theprojector 100 to the PC 300. Therefore, according to the display system1, it is also possible for the user him or herself to switch thefunction of the pen 200 between the case in which, for example, the OSof the PC 300 supports the digitizer and the case it does not.

Modified Examples

The invention is not limited to the embodiments described above, but canbe put into practice in a variety of aspects exemplified below. Further,the invention can also be put into practice in the aspects obtained bycombining the modified examples described below if necessary.

1. In the invention, the number of indication bodies is not limited.Specifically, in the invention, it is also possible to use three or moreindication bodies at the same time. In this case, the display device canconstitute the function device so as to have the same number ofinterfaces as the number of the indication bodies. It should be notedthat the number of the indication bodies can also be one. In this caseit is sufficient for the function device to have a single interface. Inthe case in which the single interface is provided alone, the displaydevice can perform switching of the device using the first methoddescribed above, namely the method of changing the configurationinformation.

2. In the projector according to the invention, it is also possible torealize the whole or a part of the constituent corresponding to theposition detection unit 110 with another device. For example, theprojector according to the invention can be configured so that animaging device (e.g., a digital camera) having a function correspondingto the imaging section 111 and the shooting control section 112 can beconnected thereto, and can be a device of obtaining the shot image datafrom the imaging device. Further, the position detection unit 110 canalso be a device other than the projector or the PC. In this case, adevice separated from the projector can be used as the positiondetection unit 110. Further, in this case, the position detection unit110 can be provided with the function corresponding to the coordinateconversion section 120.

3. Although in the embodiment section described above, the explanationis presented citing the configuration in which the display device 10 andthe host device 30 are separated from each other as an example, it isalso possible to adopt the configuration in which the display device 10has the host device 30 in the inside thereof. In this case, the displaydevice 10 is also provided with the function of the execution section32.

4. Although in the embodiment section described above the explanation ispresented citing the configuration using the pen 200 as the indicationbody as an example, it is also possible to use an indication body otherthan the pen 200. For example, it is also possible to use a finger ofthe user as the indication body.

5. The pen 200 can be provided with the configuration in which theirradiation section 230 does not irradiate the object with the light ifthe first switch 211 and the second switch 212 are not held down, andthe irradiation section 230 irradiates the object with the light if thefirst switch 211 or the second switch 212 is held down. Further, it isalso possible for the pen 200 to always irradiate the object with thelight with the irradiation section 230, and change the irradiationpattern of the light between the case in which the first switch 211 orthe second switch 212 is held down and the case in which it is not helddown. In either of the cases, whether or not the first switch 211 or thesecond switch 212 is held down (whether or not the first switch 211 orthe second switch 212 is operated) can be detected by analyzing theimage shot by the imaging section 111. Further, the projector 100 canalso output operation information (first operation information)representing the fact that the first switch 211 or the second switch 212is held down (operated), and operation information (second operationinformation) representing the fact that holding down of the first switch211 or the second switch 212 is terminated (the operation is terminated)to the PC 300. For example, the projector can also output the firstoperation information to the PC 300 as the information representing thefact that the mouse is clicked on the left button, and output the secondoperation information to the PC 300 as the information representing thefact that the left click of the mouse is terminated. Further, theprojector 100 can also output such information to the PC 300 togetherwith the identification information for identifying the pens 200, andthe coordinate information of each of the pens 200. Further, theprojector 100 can also output the operation information to the PC 300 asthe information representing the operation of a pointing device (e.g., adigitizer) other than the mouse.

6. The control data such as the coordinate information or theidentification information can be output from the projector 100 to thePC 300 with the USB communication. Further, the projector 100 can alsooutput the control data to the PC 300 with Bluetooth (registeredtrademark), a wired LAN, a wireless LAN, and so on.

7. The OSD images O1, O2, and O3 can be used in arbitrary combinationwith each other. For example, when the display of the OSD image forchanging the interface is instructed, it is possible for the projector100 to firstly display the OSD image O2 for selecting the number of theusers, and then display the OSD image O1 if the check box C21 isselected, or the OSD image O3 if the check box C22 is selected.

8. In the case in which a plurality of available pens 200 is providedand the number of the users is one, the other pens (the pens not in use)200 b than the pen 200 a used by the user can automatically be assignedto the interface (e.g., the first interface 11 a) to which the pen 200 ais assigned, or can automatically be assigned to the interface (e.g.,the second interface 11 b) to which the pen 200 a is not assigned.Further, if the number of the users is one, the pens 200 b need not beassigned to any of the interfaces.

9. Although in the embodiment described above the control section 170calculates the coordinate conversion parameters, it is also possible forthe constituent other than the control section 170 to calculate thecoordinate conversion parameters. For example, any of the constituents(e.g., the coordinate calculation section 114) inside the positiondetection unit 110 can also calculate the coordinate conversionparameters.

10. If the coordinate of the indication position calculated by thecoordinate calculation section 114 is not included in the area where theimage data is displayed, in other words, if the indication position isnot included in the display image, the coordinate conversion section 120can also set the coordinate of the position, which is included in thearea where the display image is displayed, and is near to the indicationposition, to the coordinate obtained by the conversion. According tosuch a configuration, the coordinate of the indication position can beoutput even in the case in which the position where the image is notdisplayed is indicated. Further, the coordinate output therefrom is thecoordinate of the position near to the indication position, and cantherefore be processed by the PC 300 and so on similarly to the case ofthe coordinate of the indication position.

Further, it is also possible to adopt the configuration in which thecoordinate conversion section 120 stops outputting the coordinate thusconverted in the case in which the coordinate of the indication positioncalculated by the coordinate calculation section 114 is not included inthe area where the image data is displayed, in other words, in the casein which the indication position is not included in the display image.In this case, the PC 300 can perform the operation corresponding only tothe indication to the position overlapping the image.

11. Although in the embodiment described above the normalization of thecoordinate (X1 n, Y1 n) and the coordinate (X2 n, Y2 n) is performed inthe range equal to or higher than 0 and equal to or lower than 1, themethod of normalization is not limited thereto. For the normalization ofthese coordinates, there can be used an arbitrary value (e.g., the rangeequal to or higher than 0 and equal to or lower than 32767) definedlogically.

12. The display device according to the invention is not required to bea projector. For example, the display device according to the inventioncan also be a liquid crystal display. In this case, the constituentcorresponding to the detector 14 can also be a digital still camera orthe like, but can also be realized by a touch screen (a touch panel)disposed so as to overlap the display surface. Further, as the detectionsection 14, a variety of constituents well known to the public can beused besides the touch screen. It should be noted that in the case inwhich the display device according to the invention has the displaysurface itself, the operation such as the calibration described abovebecomes unnecessary.

13. Although in the embodiment described above the explanation ispresented citing, as an example, the configuration in which the lightmodulation device 145 uses the three transmissive or reflective liquidcrystal panels corresponding to the respective colors of RGB as meansfor modulating the light emitted by the light source, the invention isnot limited thereto, but can be configured using a system including oneliquid crystal panel and a color wheel combined with each other, asystem using three digital mirror devices (DMD), a DMD system using onedigital mirror device and a color wheel combined with each other, and soon. Here, in the case of using just one liquid crystal panel or DMD asthe display section, the member corresponding to the combining opticalsystem such as the cross dichroic prism is not necessary. Further,besides the liquid crystal panel or the DMD, any configuration capableof modulating the light emitted from the light source can be adoptedwithout problems.

14. Further, it is also possible for the projector 100 to download thecontrol program, which is stored in the storage section 180 in theembodiment described above, from another device connected via thecommunication network, and then execute the control program, or it isalso possible to adopt the configuration of recording the controlprogram on a portable recording medium, retrieving each of the programsfrom the recording medium, and then executing the program. The same canbe applied to the display control program stored by the PC 300, and itis also possible for the PC 300 to download the display control programfrom another device and then execute the program, or it is possible toadopt the configuration in which the PC 300 retrieves the displaycontrol program stored in a portable recording medium, and then executesthe program.

The entire disclosure of Japanese Patent Application No. 2012-1018,filed Jan. 6, 2012 is expressly incorporated by reference herein.

What is claimed is:
 1. A display device comprising: a function deviceconnected to a host device in a manner compliant with a USB (UniversalSerial Bus) standard, and having a first interface; a storage sectionadapted to store a plurality of pieces of configuration informationincluding first configuration information adapted to make a firstpointing device correspond to an interface; a display section adapted todisplay an image on a display surface; a detector adapted to detect afirst position indicated by a first indication body to the displaysurface; a supply section adapted to assign the first configurationinformation stored in the storage section and first coordinate datarepresenting the first position detected by the detector to the firstinterface, and supply the host device with the first configurationinformation and the first coordinate data via the function device; areception section adapted to receive an operation of a user; and achange section adapted to change the configuration informationcorresponding to the first coordinate data in accordance with theoperation received by the reception section.
 2. The display deviceaccording to claim 1, wherein the function device includes the firstinterface and a second interface, the storage section stores the firstconfiguration information, and second configuration information adaptedto assign a second pointing device different from the first pointingdevice to an interface, the change section changes the interface, towhich the supply section supplies the first coordinate data, from thefirst interface to the second interface in accordance with theoperation, and the supply section assigns the second configurationinformation and the first coordinate data to the second interface, andsupply the host device with the second configuration information and thefirst coordinate data via the function device.
 3. The display deviceaccording to claim 1, wherein the function device includes the firstinterface and a second interface, the storage section stores the firstconfiguration information, and second configuration information adaptedto assign a second pointing device different from the first pointingdevice to an interface, the detector detects the first position, and asecond position indicated by a second indication body to the displaysurface, the supply section assigns the first configuration informationstored in the storage section and the first coordinate data representingthe first position detected by the detector to the first interface andsupplies the host device with the first configuration information andthe first coordinate data via the function device, and assigns thesecond configuration information stored in the storage section andsecond coordinate data representing the second position detected by thedetector to the second interface and supplies the host device with thesecond configuration information and the second coordinate data via thefunction device, and the change section changes at least either of thefirst configuration information and the second configuration informationsupplied from the supply section in accordance with the operationreceived by the reception section.
 4. The display device according toclaim 1, wherein the change section changes the configurationinformation so that a class of a device assigned to the first interfacefrom one of a mouse and a digitizer to the other.
 5. The display deviceaccording to claim 2, wherein the storage section stores theconfiguration information, which assigns HID (Human Interface Device)class to the first interface and the second interface.
 6. The displaydevice according to claim 5, wherein the storage section stores theconfiguration information, which assigns a sub-class corresponding to amouse to the first interface, and assigns a sub-class corresponding to adigitizer to the second interface.
 7. The display device according toclaim 5, wherein the storage section stores the configurationinformation, which assigns a sub-class corresponding to a mouse to thefirst interface and the second interface.
 8. The display deviceaccording to claim 5, wherein the storage section stores theconfiguration information, which assigns a sub-class corresponding to adigitizer to the first interface and the second interface.
 9. Thedisplay device according to claim 1, wherein the display sectiondisplays the image on the display surface by projecting light.
 10. Adisplay system comprising: a display device including a function deviceconnected to an external device in a manner compliant with a USB(Universal Serial Bus) standard, and having a first interface, a storagesection adapted to store a plurality of pieces of configurationinformation including first configuration information adapted to make afirst pointing device correspond to an interface, a display sectionadapted to display an image on a display surface, a detector adapted todetect a first position indicated by a first indication body to thedisplay surface, a supply section adapted to assign the firstconfiguration information stored in the storage section and firstcoordinate data representing the first position detected by the detectorto the first interface, and supply the external device with the firstconfiguration information and the first coordinate data via the functiondevice, a reception section adapted to receive an operation of a user,and a change section adapted to change the configuration informationcorresponding to the first coordinate data in accordance with theoperation received by the reception section; and a host device includingan execution section connected to the display device in a mannercompliant with the USB standard, and adapted to execute a processcorresponding to the first position in accordance with the configurationinformation and the first coordinate data supplied via the functiondevice.
 11. The display system according to claim 10, wherein theexecution section executes a process of making the display section drawan image corresponding to the first position.
 12. A method of switchinga device in a display device including a function device connected to ahost device in a manner compliant with a USB (Universal Serial Bus)standard, and having a first interface, a storage section adapted tostore a plurality of pieces of configuration information including firstconfiguration information adapted to make a first pointing devicecorrespond to an interface, and a display section adapted to display animage on a display surface, the method comprising: a first step ofdetecting a position indicated by an indication body to the displaysurface; a second step of assigning coordinate data representing theposition detected in the first step and the configuration informationstored in the storage section to the first interface, and supplying thehost device with the coordinate data and the configuration informationvia the function device; a third step of receiving an operation ofchanging the configuration information, which is assigned to the firstinterface, from a user; a fourth step of changing the configurationinformation corresponding to the coordinate data from the coordinatedata supplied in the second step in accordance with the operationreceived in the third step; a fifth step of detecting, after the changein the fourth step, a position indicated by the indication body to thedisplay surface; and a sixth step of assigning coordinate datarepresenting the position detected in the fifth step and theconfiguration information changed in the fourth step to the firstinterface, and supplying the host device with the coordinate data andthe configuration information via the function device.